Three-quarters of COPD cases have their origins in poor lung function pathways beginning in childhood, according to a cohort study published in The Lancet Respiratory Medicine journal.A second study in the journal suggests that there could be a window of opportunity during childhood to reduce the risk of poor lung function in later life."These findings highlight the importance of preventing both early life adverse exposures that could lead to poorer lung growth and adult risk factors contributing to accelerated lung decline," says Professor Shyamali Dharmage from School of Population and Global Health, The University of Melbourne, Australia.COPD is expected to be the third-largest cause of death globally by 2030."It is important that we identify its key causes so that this burden can be reduced," Dharmage added.Reduction of maternal smoke exposure and personal smoking and promotion of immunisation are identified as public health targets to prevent poor lung function pathways."Doctors and patients with asthma should be made aware of the potential long-term implications of non-optimal asthma control throughout life, and this should be investigated in future research," the study authors noted.In the first study, 2,438 participants from the Tasmanian Longitudinal Health Study (Australia) were tracked from childhood to the age of 53.In the second study, 2,632 participants were tracked from birth to 24 years old and their lung function was measured.In the second study, the authors found that around three-quarters of infants aged one to six months with poor lung function improved throughout their childhood, indicating a window of opportunity to increase lung function and potentially reduce risk of COPD in later life.Interventions to maximise lung growth in early childhood might modify the risk of COPD in older age, they noted.